In the semiconductor fabrication arts, it is often necessary to fashion (etch, pattern, etc.) layers of differing materials according to a given design to create electronic devices, interconnections, or other structures in an integrated circuit. Photolithography is commonly used to create patterns within the layers of an integrated circuit. FIG. 1A-1C illustrates a typical photolithography process. As shown in FIG. 1A, a photoresist material 1 is deposited atop a first layer 2 that is to be etched. Layer 2 may overlay any number of other layers, for example, layer 3. According to well known masking, exposing, and developing techniques, the photoresist material 1 is patterned to create an opening 4. Layer 2 may then be etched through the opening, such as by a reactive ion etch (RIE), shown in FIG. 1B. The RIE utilizes an etchant 5 that etches the material of layer 2, more selectively than the photoresist material 1. Hence, the photoresist material 1 holds its form during the etch and a cavity 8 can be formed into layer 2 according to the patterned opening 4. At the same time, the etchant 5 that etches layer 2, does so at a much higher rate than it etches the material of underlying layer 3, hence the underlying layer 3 acts as an etch stop.
Typically, after forming the cavity 8 in layer 2, the photoresist material 1 needs to be removed to enable further processing of layer 2 or layer 3. Consequently, as shown in FIG. 1C, the photoresist material 1 may be removed according to the similar etching methods, such as RIE, O2 high pressure ashing, and/or well-known wet cleaning techniques. Layer 2 and layer 3 are typically durable semiconductive, insulative, or conductive materials that are conventionally used in integrated circuits, so that during the removal of the photoresist material 1, layers 2 and 3 do not typically have to be protected when the photoresist material 1 is being removed. Additionally, the oxygen plasma damage from RIE is very minimal on these types of materials. Examples of durable materials may include silicon, silicon oxide, silicon nitride, polysilicon, and other materials that are durable to chemistries that remove conventional photoresist materials. As a result, the photoresist material 1, has, until now, been removed without fear of damaging underlying thin films or structures.
However, modern technologies are rapidly exploring the use of new and different materials that have not typically been used in the formation of integrated circuits. These new and different materials may include materials that are sensitive to chemistries that, until now, have not presented problems. For example, germanium has been proposed to replace silicon as a semiconductor of choice for many fabrication processes that heretofore have used silicon. Germanium, however, tends to be very sensitive to certain chemistries, for example, the dry and wet chemistries utilized to remove photoresist materials. Consequently, previous methods of removing certain materials, such as photoresist, require new and unique techniques in order to maintain the integrity of new and different materials, such as germanium.